A number of types of chin straps for athletic helmets including football helmets are known in the prior art. One type includes a soft flexible chin cup having attaching straps stitched to its opposite sides and being adapted for connection with fastener means on the opposite sides of the helmet. This device includes a cloth lining for the flexible chin cup. The device offers little protection to the chin and tends to irritate the chin, sometimes producing skin infection due to abrasion in the presence of perspiration and accumulated dirt. Moreover, the stitching connecting the attaching straps to the chin cup tend to fail. The overall flexibility of the prior art structure largely defeats the main purpose of the present invention which is the elimination of movement of the helmet on the head while the chin strap is in place.
Other known prior art chin straps involve the use of cup elements which are separate from a strap assembly and are held removably in a slit separated central portion of the strap. The arrangement is not secure and does not adequately protect the chin and prevent pivoting or other movement of the helmet on the head. This latter prior art chin strap arrangement is shown in U.S. Pat. No. 3,619,813.
Prior U.S. Pat. Nos. 3,166,761; 3,916,446 and 4,051,556 show further helmet chin strap structures which suffer from the defects noted above or other defects, such as unduly complex and costly construction, insecure or weak attachment means, or the use of materials which make it difficult or impossible to maintain the device in a clean sanitary condition by washing.
In contrast to the prior art, the present invention provides a helmet chin strap unit formed of a synthetic elastomer possessing an elastic memory. The improved chin strap very adequately achieves the primary objective of the invention in securing the helmet against movement on the head, while simultaneously providing very good protection to the chin. The elasticity of the strap extensions of the device cause the helmet to return automatically to its correct position on the head following heavy blows which will cause some momentary shifting of the helmet. The elastic memory of the material of which the device is made assures the returning of the displaced helmet to its normal protective position on the head.
Moreover, the material employed is susceptible to very easy washing and a unique apertured chin cushioning pad within the cup of the chin strap secures the tip of the chin safely within a space defined by the interior of the cup. The cup, which is quite rigid at its center, protects the chin from direct blows. The chin cushioning pad or insert is also formed of materials which are readily washable and which do not tend to irritate and abrade the skin.
In accordance with the present invention, the geometry of the chin strap device is carefully conceived to provide a four point anchorage to the helmet through two pairs of divergent axis straps which are integrally joined to the opposite sides of the chin cup by wide twist-resistant and relatively stiff joint portions. The attaching strap extensions themselves are relatively flexible but are very strong. The device is completely without stitching or other connecting means subject to failure.
Another important feature of the invention is that the chin cup is contoured on two axes to properly fit the chin and diminishes gradually in thickness from the center of the cup which is quite rigid toward its marginal edges which are comparatively less rigid, although stiff in comparison to the strap extensions. The wide joints between the strap extensions and the chin cup derive rigidity and resistance to twisting from their widths and thicknesses along with a rigidifying effect caused by the channel formation of the chin cup where it blends into the wide joints between it and the strap extensions.
One of the most important aspects of the invention derived from its construction as discussed above is the substantial elimination of the so-called "rebound effect" caused by movement of the helmet on the head in response to a blow. The heavier the blow the greater the rebound effect produced under the prior art. With the present invention, this problem to a great extent is eliminated by the ability of the chin strap to hold the helmet securely on the head with some of the impact forces being transmitted to the chin and jaw through the improved chin strap.
Other objects and advantages of the invention will become apparent to those skilled in the art during the course of the following description.